1. Field of the Invention
The present invention relates to a cradle having a panhead function that rotates an image pickup device, such as a digital camera, around two axes perpendicularly to each other, that is, in a pan direction and a tilt direction.
2. Description of the Related Art
Cradles having a panhead function have been known that rotate an image pickup device, such as a digital camera, around two axes perpendicularly to each other, that is, in a pan direction and a tilt direction. In Japanese Laid-Open Patent Publication (Kokai) No. 2002-131806, to such a cradle is mounted an image pickup device. This cradle is constituted by a motor-driven panhead including a digital camera portion, a drive portion that rotates the camera portion in a horizontal direction (a pan direction), and a drive portion that rotates the camera portion in a vertical direction (a tilt direction).
The digital camera portion is rotated by the motor-driven panhead in the pan direction and the tilt direction to perform shooting of an object image in a desired direction. Then, the digital camera portion transmits a picked-up image to an information processing device such as a personal computer (PC) as electronic data, and projects the image onto a monitor. Alternatively, the digital camera portion can transmit the picked-up image to a remote location by a communication device to store and play back the image.
The motor-driven panhead includes a pan motor and a tilt motor as drive portions, and a reduction gear mechanism (a transmission mechanism such as a gear that transmits a driving force) corresponding to each motor, for a rotation of the digital camera portion. Generally, the motor-driven panhead is configured so that any one of the motors, for example, the tilt motor is mounted to a pan base for a pan rotation, and a rotation in a pan direction causes a tilt motor body to be rotated with the pan base (see Japanese Laid-Open Patent Publication (Kokai) Nos. 2002-131806, 2001-157093, and 2000-270316).
An image pickup device having a motor-driven panhead function can be provided with a mechanism that can transmit and receive electronic data to and from an information processing device by a wireless technique to facilitate processing of the electronic data. Such a wireless image input device is expected to increase since the installation location thereof is not limited. To the cradle, a wide range of devices may be mounted such as a sound collecting microphone that is to be panned or tilted besides the digital camera.
Other cradles having a panhead function having been known that rotate a shooting direction of an image pickup device, such as a digital camera, in a pan direction and a tilt direction. (see Japanese Patent No. 3336698 and Japanese Laid-Open Patent Publication (Kokai) No. 2001-223919).
In recent years, the capacity of an image pickup device has been increasing with increasing performance of a shooting function, while a convenient cradle having a panhead function has been desired that can be easily carried and installed by reducing the sizes of a movable portion of an image pickup device and a cradle having a panhead function.
However, as described above, for the motor-driven panhead in which the tilt motor is mounted to the pan base, the tilt motor body is rotated together with the pan base in panning the camera portion. This requires a much larger space (an operation space) to be ensured for the rotation of the motor-driven panhead in the pan direction than the sizes of the tilt motor and the tilt reduction gear mechanism. Specifically, obstacles cannot be placed on rotation paths of the tilt motor and the tilt reduction gear mechanism so that rotations thereof are not prevented during the rotation in the pan direction.
Thus, the pan motor or the like has to be placed in positions other than on the rotation paths. This requires a large space for the device body to increase an installation space. If the tilt or pan reduction gear mechanism is reduced in size for reducing the operation space of the motor-driven panhead, driving torque of the motor becomes insufficient. Insufficient torque may reduce an operation speed of the pan or the tilt.
During the rotation of the pan base in the pan direction, an electric harness of the tilt motor may be entangled by the operation. Further, reliable wiring has to be performed for preventing breaking due to repeated bending of the electric harness, which makes the wiring difficult.
These problems still remain when the pan motor is mounted to a tilt base contrary to the above.
A general cradle having a panhead function includes two independent motors: a tilt motor and a pan motor for rotating an image pickup device in a pan direction and a tilt direction. In this case, the tilt motor itself is rotated in the pan direction together with the image pickup device during a rotation in the pan direction.
Thus, the pan motor has to be placed in a position other than on a rotation path so that a rotation of the tilt motor in the pan direction is not prevented. The pan motor requires torque considering the mass of the tilt motor besides the mass of the image pickup device.
This increases the sizes of a movable portion of the image pickup device and the pan motor, and makes control of the two motors complicated. Electric wiring to the tilt motor becomes also complicated, limiting an increase in speed of the rotation in the pan direction and the tilt direction.